BRITAIN'S FIRST ICOS-FLEX WALL INSTALLED IN LONDON

The details are given of a construction which demonstrates the advantages of the Icos-Flex system of diaphragm walling. Post-tensioned diaphragm walling was employed in the innovation which proved that 9 m deep basement walls could be econimically constructed "free standing" without ground anchors, counterforts or props. The absence of obstructions within the perimeter walls allowed rapid bulk excavation to formation level. The relative independence of the Icos construction stage from the subsequent building programme proved advantageous. Constructions of the above type require an appropriate toe-in length (which provides the panel with good load bearing capacity and resolves support problems) which is representative of the particular ground conditions. The construction scheme described here required 105 linear meters of Icos-Flex wall of which 56 m were cast 0.9 m thick and the remainder 0.8 m. The latter penetrated to a depth of 13.04 m, whereas 16 m was specified for the thicker wall. These dimensional differences are due to the necessary height of the cantilever which was 7.22 m and 9.64 m respectively, and the capping beam variations of 1.6 m and 0.8 m. The latter had to suit adjacent road levels where traffic flow remained unimpeded. The work was divided into 28 post-tensioned panels and one conventional Icos element, excavated in 3-3.5 m panel lengths. Concrete specifications called for a 28-day cube strength of 32/MN/m(sq.) in the diaphragm walls and for 34.5 MN/m(sq) in the capping beams. Detaills of the construction are given including the trenching operations. The location of the tendons is described. The advantages of the apparent rigidity of the panel in the ground, the application of the cantilever moment, traditional underpinning and sundry preparatory work are discussed.

  • Availability:
  • Corporate Authors:

    Foundation Publications Limited

    7 Ongar Road
    Brentwood CM15 9AU, Essex,   England 
  • Publication Date: 1975-3

Media Info

  • Features: Figures;
  • Pagination: p. 26-28
  • Serial:
    • GROUND ENGINEERING
    • Volume: 8
    • Issue Number: 2
    • Publisher: EMAP CONSTRUCT LIMITED
    • ISSN: 0017-4653

Subject/Index Terms

Filing Info

  • Accession Number: 00097382
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Aug 13 1975 12:00AM